The present invention relates to cleaning elements in an automatic car wash line, and more particularly, to a dryer element of the type mounted to pivot in upward arc as a vehicle passes thereunder, while closely following but not touching the vehicle contour.
U.S. Pat. No. 4,651,442 discloses a nozzle assembly for a vehicle drying apparatus in which the drying station has an overhead gantry under which the vehicle travels when passing through the cleaning line. A boom is mounted to the overhead gantry for pivotal movement about a pivot axis extending in a direction transverse to the cleaning line. A dryer element has a housing with a plurality of slots oriented substantially transversely to the direction of the passing vehicle, thereby defining nozzles for discharging air on the vehicle surface to remove water or other cleaning liquid applied at a previous cleaning station. The dryer element is mounted on the boom at a point remote and in a fixed, spaced apart relation with the pivot axis for arcuate movement with the boom and provides a directional discharge of the drying air toward the passing vehicle. The dryer element and nozzle rotate relative to the boom to redirect the directional discharge of the drying air as the boom and nozzle follow the contour of the passing vehicle such that the air discharge angle relative to vertical, remains substantially constant. The dryer element follows the contour of the vehicle by means of a pair of wheels that are lightly preloaded downwardly by air cylinders. The necessity in the '422 patent of relying on a biased contact between the contour following roller wheels and the surface of the vehicle, carries with it the significant disadvantage that particulates and the like which find their way between the wheels and the surface of the automobile frequently result in scratches or other permanent marks on the vehicle. Relying on contact means for following the contour does offer the advantage that a very close spacing between the discharge nozzle and the vehicle surface can be maintained, which promotes good drying, but this advantage is significantly undermined by the frequency of scratching and the like of the vehicle finish.
In U.S. Pat. No. 4,730,401, a contactless dryer arrangement is disclosed, in which a dryer element is controlled for movement relative to the contour of the vehicle, by a light beam passing with clearance under the drying element and a device controller responsive to interruption of the light beam for operating the travel and lift motors associated with the drying element. This arrangement is disclosed, however, in the context of a washer and dryer station wherein the vehicle to be washed is stationary, and a frame travels longitudinally and vertically relative to the vehicle, to first perform a washing operation, and then a drying operation. Although this system is contactless, it is not readily adaptable for use in a gantry with pivoting boom arrangement of the type disclosed in U.S. Pat. No. 4,651,442, wherein both the vehicle and the dryer element are moving simultaneously.
Similarly in U.S. Pat. No. 3,533,422 a washing arrangement is described, with an indication that the same could be used for a dryer system, wherein the vehicle is driven into an enclosure within which a frame moves vertically and horizontally to apply fluid to the surface of the vehicle. In this patent, a contactless vehicle contour following means is disclosed, wherein a sensor assembly includes a plurality of sensor combinations for sensing the general elevational contours of the vehicle. Each of the sensor combinations includes an upper sensor unit and a lower sensor unit, each sensor unit including an emitter mounted on the frame on the first side of the vehicle and a receiver mounted on the frame on the second opposite side of the vehicle at the same level as the emitter, for transmitting and receiving radiant energy, respectively. One of the sensor combinations operates to control the movement of the wash bar when the frame is moved rearwardly and the other controls the movement of the wash bar during forward movement of the frame. In a given sensor combination, the lower sensor is connected to a suitable drive means to lower the wash bar when the receiver is activated by the transmission of radiant energy from the associated emitter. The other sensor unit is activated to move the spray arm upwardly relative to the vehicle and to contemporaneously therewith stop the longitudinal movement of the frame relative to the vehicle, when the transmission of radiant energy between the emitter and receiver is blocked. Thus, although multiple transmitters and receivers are employed, this system is not adapted for use in the pivoting boom type arrangement, wherein both the vehicle and the cleaning element are in motion.
U.S. Pat. No. 3,410,284 illustrates another contactless washing or drying system, wherein a dual sensor arrangement is utilized to control the movement of a washing or drying nozzle where both the vehicle and the cleaning element move relative to each other. In this system, the cleaning element moves only vertically, while the vehicle moves horizontally. One sensor is associated with a nozzle which discharges fluid in the direction a vehicle travel, and the other sensor is associated with a nozzle which discharges in the direction downstream of the vehicle travel. These sensors and nozzles are used in the alternative, depending on the longitudinal position of the vehicle, relative to the vertical movement of the cleaning element. As with the previously described systems, the control technique discloses this patent is not readily adaptable for use with the pivotable cleaning arrangement shown in the U.S. Pat. No. 4,651,442.
U.S. Pat. No. 4,718,439 illustrates a mountry and control arrangement for a cleaning element of a vehicle washing system, having a gantry and pivoting boom, the movement of which is controlled by two sets of radiant energy sensors. The system disclosed in U.S. Pat. No. 4,718,439 is adapted for following the contour of a vehicle with substantial clearance in connection with a washing or rinsing operation, e.g., with a space of approximately 10.5 inches. Even if the system of this patent were to be fitted with a drying element rather than a washing or rinsing element, the control system disclosed therein, which may be suitable for maintaining a spacing of 10.5 inches or so, would not be adequate for maintaining a nominal drying distance of approximately two inches, which is the maximum distance required for accomplishing superior drying.